Are monolinguals more common than people who speak more than one language in the world? 

Many monolinguals tend to have the view that the state of monolingualism within an individual and within society is the most logical, acceptable and prevalent in the world. Yet, the reality is that bilinguals are in the majority in the world. Various estimates exist of what percentage of the world is bilingual. This is very difficult, because the definition of bilinguals may include or exclude those who have a little fluency in one language.

When local dialects are added into the confusion of producing an accurate figure, any percentage will be inaccurate. Published estimates tend to vary between 60% and 75% of the world as bilingual. The conclusion is clear. Bilinguals are in the majority in the world, not monolinguals.